Nissan Repair: Car Repair, neddle, autozone

Question
96 Nissian Maxima RPM Neddle Jumps Around How Can I Solve this Problem  

Answer
Byron,

Either the tach is defective or the wiring feeding the tach is messed up.  That is, the wire that feeds the tach has a resistor and filter in line.  Use a scanner to look at the data stream feeding the tach.  If the data that the computer is getting fluctuates then the wiring or resistance is defective.  If you get a correct reading on the scanner then your tach is defective and needs to be replaced.  You could try Autozone or Checker since they scan fro free.  But, they might not want to do the tach test.  You can purchase a scanner for $100 bucks that does the tach test along with all codes.  Yes, $100 bucks is expensive but you can use it on any car from 1996 and newer.